Compressor

ABSTRACT

A compressor having a structure for reducing vibration and noise from an internal structure is disposed. The compressor includes a sealed case, an internal structure having a driving part disposed in the sealed case for generating a driving force to compress a fluid, and a compressing part disposed in the sealed case for compressing the fluid, and a weight attached to the sealed case having a predetermined mass to reduce vibration and noise generated by the internal structure. Since there is no need to newly manufacture the sealed case or to add an absorber for the purpose of reducing vibration and noise from an already assembled compressor, time and costs are also saved.

REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 2005-5333, filed on Jun. 21, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a compressor, and more particularly, to a structure of a compressor capable of reducing vibration and noise from an internal structure of the compressor.

2. Description of the Related Art

Generally, a compressor includes a driving part for rotating a rotation shaft fixed to a rotor caused by electrical interaction between a stator and the rotor to generate a driving force, a compressing part for compressing a fluid using the driving force, and a sealed case for protecting the components such as driving part, the compressing part, and the like and forming an external appearance of the compressor. Compressors are grouped into a reciprocation type compressor, a rotary type compressor, and a scroll type compressor.

FIG. 1 shows an example of the reciprocation type compressor from among the above-described compressors. As shown in FIG. 1, the reciprocation type compressor includes a sealed case 1 having a predetermined internal space, a driving part 2 installed in the sealed case 1 to generate a driving force, and a compressing part 3 for compressing a fluid. The sealed case 1 is made by coupling an upper case 1 a with a lower case 1 b.

In this compressor, when the driving force is generated from the driving part 2, when the driving force is consumed by the compressing part for the compression, and when a fluid is compressed and the compressed fluid is discharged, a great deal of vibration and noise is generated, some of which can be eliminated by a vibration absorbing device and a noise absorbing device.

However, when a rate of rotation of the rotation shaft in the compressor is gradually increased, frequency of vibration generated from the internal structure of the compressor may become the same as the natural frequency of the sealed case, resulting in a resonant state so that the vibration and noise are maximized.

When the vibration and noise is transmitted to the exterior of the compressor, the impact on a user is increased and the life span of the compressor is decreased.

Moreover, in order to reduce vibration and noise from an already assembled compressor, a new sealed case is made of a material and a shape different from the sealed case of the already assembled compressor or a separate vibration absorber is attached to the already assembled compressor. However, those arrangements are complicated, time consuming, and require a great deal of costs.

SUMMARY OF THE INVENTION

The present invention has been made in- view of the above-mentioned problems, and an aspect of the invention is to provide a compressor in which the natural frequency of a sealed case is changed to prevent resonance of the compressor, to prevent vibration and noise from maximizing even when the compressor rotates at a high rotation speed, and to simply reduce vibration and noise from an already assembled compressor.

In accordance with one aspect, the present invention provides a compressor, which included a sealed case, an internal structure having a driving part provided in the sealed case to generate a driving force to compress a fluid, and a compressing part for compressing the fluid, and a weight provided in the sealed case having a predetermined mass to reduce vibration and noise generated by the internal structure.

Preferably, the weight includes a neck portion extended from a contacting part contacting the sealed case and being bent, and a free end portion formed by bending the neck portion and spaced apart from the sealed case.

The free end portion is preferably bent and a part thereof is preferably welded to the sealed case.

Moreover, the weight could have a predetermined area and be fixed to the inner surface or the outer surface of the lower side of the sealed case.

The neck portion is preferably provided with a spring, the weight could have a welding part to be welded to the sealed case by a spot welding, and the neck portion could be thinner than the free end portion.

With those and other objects, advantages and features of the invention that may become hereinafter apparent, the nature of the invention may be more clearly understood by reference to the following detailed description of the invention, the appended claims and to the several drawings attached herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing of a cross sectional view illustrating a prior art compressor;

FIG. 2 is a drawing of a partial cross sectional view illustrating a lower case of a compressor to which a weight is attached according to a preferred embodiment of the present invention;

FIG. 3 is a drawing of several partial cross sectional views of the weight of the compressor according to the preferred embodiment of the present invention, in which FIGS. 3 a, 3 b, 3 c, and 3 d are views illustrating respective weights of compressors according to first, second, third, and fourth embodiments of the present invention;

FIG. 4 is a drawing of the inside of the lower case of the compressor to which the weight is attached, in which FIG. 4 a shows the weight shown in FIG. 3 a, and FIG. 4 b shows the weight shown in FIG. 3 d; and

FIG. 5 is a drawing of frequency response curves of noise in the compressor according to the preferred embodiments of the present invention, in which FIG. 5 a shows a frequency response curve at 2,880 rpm and FIG. 5 b shows a frequency response curve at 3,480 rpm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a drawing of a partial cross sectional view illustrating a lower case of a compressor to which a weight for reducing vibration and noise is attached according to a preferred embodiment of the present invention. FIG. 4 shows a structure of the compressor with the weight for reducing vibration and noise attached to the inner surface of the lower case of the compressor. FIG. 3 shows respective structures for installing the weight for reducing vibration and noise according to the preferred embodiments of the present invention, in which FIGS. 3 a, 3 b, 3 c, and 3 d show first, second, third, and fourth preferred embodiments of the present invention, respectively.

As shown in FIG. 2, the compressor according to the preferred embodiment of the present invention includes a sealed case 10 having a predetermined internal space. The sealed case 10 includes an upper sealed case (not shown) and a lower case 10 b. Since the internal structures such as the driving part (not shown) and the compressing part (not shown) installed in the sealed case 10 are identical to those of the conventional compressor, the internal structures are omitted from the drawings.

Here, the compressor includes the reciprocating type compressor, the rotary type compressor, and the scroll type compressor. When the compressor in which the compression of a fluid is performed is located in the internal space of the lower case 10 b, significant vibration and noise are generated from the lower side of the lower case 10 b. The reason is because vibration and noise are concentrated due to the eccentric rotation and high change of pressure generated during the compression of the fluid.

FIG. 3 a shows the compressor according to the first preferred embodiment of the present invention. The weight 50 having a predetermined mass is fixed to the inner surface of the lower side of the lower case 10 b by spot welding. Here, the spot-welded position is referred to as welding part 51.

FIG. 3 b shows another view of the compressor according to the second preferred embodiment of the present invention. The weight 50 is fixed to the outer surface of the lower side of the lower case 10 b by spot welding.

Meanwhile, it is possible to fix the weights 50 to the outer surface and the inner surface of the lower side of the lower case 10 b by simultaneously applying the first preferred embodiment and the second preferred embodiment of the present invention as shown in FIGS. 3 a and 3 b.

FIG. 3 c shows still another view of the compressor according to the first preferred embodiment of the present invention. The weight 50 is fixed to the inner surface of the lower side of the lower case 10 b by spot welding. The weight 50 has a neck portion 53 formed by extending and bending a closely contacting part 52 closely contacting the lower case 10 b, and a free end portion 54 formed by bending the neck portion 53. Some of the free end portion 54 is bent and welded to the lower case 10 b. In this welding, spot welding is not required. With regard to the neck portion 53, in order to increase the efficiency of damping the vibration, springs 55 are installed to the outer sides of the neck portion 53. The neck portion 53 is sufficiently thin that the neck portion 53 can serve as an elastic body together with the springs 55.

FIG. 3 d shows yet another view of the compressor according to the first preferred embodiment of the present invention. The weight 50 is fixed to the inner surface of the lower side of the lower case 10 b by spot welding. The weight 50 has a neck portion 53 formed by extending and bending a closely contacting part 52 and a free end portion 54 formed by bending the neck portion 53. The free end portion 54 is spaced apart from the lower case 10 b, and springs 55 are installed on the outer sides of the neck portion 53 in the same way as shown in FIG. 3 c.

Hereinafter, operation of the invention for reducing vibration and noise in the compressors according to the preferred embodiments of the present invention will be described in detail.

If the natural frequency of the sealed case is set to f when vibration caused by the internal structures of the compressors is transmitted to the sealed case, the natural frequency f can be expressed as the following formula. $\begin{matrix} {f = {\frac{1}{2\pi}\sqrt{\frac{k}{m}}}} & (1) \end{matrix}$

Here, k represents the rigidity of the sealed case and m represents the mass of the sealed case. In other words, the natural frequency can be reduced by increasing the mass of the sealed case. When the natural frequency f is decreased as a result, the resonance caused by increase in the frequency of vibration generated from the internal structures can be avoided. In other words, by adding the weight to the sealed case, the natural frequency of the sealed case decreases and the frequency of vibration generated inside the compressors may become the same as the natural frequency of the sealed case, since in this case, the vibration and the noise are not very high, it does not matter. When the compressors rotate at a high rotation speed, the resonance phenomenon can be avoided, and although the frequency of the vibration generated inside the compressors is high, vibration can be reduced at a high RPM of the compressors.

Thus, by simply installing the weight to an already assembled compressor, vibration generated when the compressor rotates at a high rotation speed can be reduced without newly manufacturing a sealed case or adding a vibration absorber.

Also, since ambient air is also vibrated when vibration occurs, an acoustic wave is generated. The acoustic wave becomes noise when the intensity of the acoustic wave is increased. Since energy caused by the vibration is proportional to the intensity, I, of sound and the intensity, I, of sound is proportional to the magnitude of noise, and since vibration is reduced by which the resonance is prevented when the compressors according to the preferred embodiments of the present invention rotate at a high rotation speed, vibration and noise are simultaneously reduced.

FIGS. 5 a and 5 b show frequency response curves with respect to noise measured at a frequency band of 10 kHz when the weight is installed to the compressor according to the first preferred embodiment of the present invention and the compressor rotates at a high rotation speed of 2,880 rpm and 3,480 rpm respectively. In the drawings, a broken line represents a frequency response curve of a conventional compressor, and the solid line represents a frequency response curve of the compressor according to the first preferred embodiment of the present invention. As one can see from experimental results as shown in FIG. 5, the compressor according to the first preferred embodiment of the present invention has an improved noise reduction at a high rotation speed faster than 2,800 RPM.

Also, the weight 50 in FIG. 3 d has a structure for more effectively absorbing vibration generated from the internal structures and transmitted to the sealed case and performs a similar function as a kind of a vibration absorber. In other words, the sealed case becomes a first massive body, the neck portion 53 and the springs 55 serve as devices for applying elastic force, and the free end portion 53 serves as a second massive body so that the vibration transmitted to the sealed case vibrates only the free end portion 54 through the neck portion 53 and the springs 55 and, consequently, disappears. Thus, an exciting force is applied from the internal structure of the compressor to the sealed case and is transmitted to the weight. Since the exciting force makes only the free end portion vibrate, it is transformed into kinetic energy or thermal energy and disappears, and, as a result, vibration is absorbed without vibrating the sealed case.

As a result, the compressor according to the present invention can significantly reduce vibration and noise through use of the weight as shown in FIG. 3.

As described above, according to the compressor of the present invention, by adding a weight with a simple structure, vibration and noise transmitted from the inside to the exterior of the compressor can be reduced. Moreover, even when reducing vibration and noise from an already assembled compressor, since there is no need to newly manufacture a sealed case or to add a vibration absorber, the compressor of the present invention has advantages in view of time and costs.

It should be emphasized that the above-described embodiments of the present invention, and particularly, any preferred embodiments, are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiments of the invention, without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims. 

1. A compressor comprising: a sealed case forming an internal structure, the internal structure comprising a driving part disposed in the sealed case adapted to generating a driving force for compressing a fluid, and a compressing part adapted to compressing the fluid; and a weight attached to the sealed case and having a predetermined mass, wherein the weight reduces vibration and noise generated by the internal structure.
 2. The compressor according to claim 1, wherein the weight has a predetermined area and is attached to an inner surface of a lower side of the sealed case.
 3. The compressor according to claim 1, wherein the weight has a predetermined area and is attached to an outer surface of a lower side of the sealed case.
 4. The compressor according to claim 1, wherein a portion of the weight is welded to the sealed case by spot welding.
 5. The compressor according to claim 1, wherein the weight is used when the compressor is rotated at a high rotation speed faster than 2,800 RPM so that vibration and noise are reduced.
 6. A compressor comprising: a sealed case forming an internal structure, the internal structure comprising a driving part disposed in the sealed case adapted to generating a driving force for compressing a fluid, and a compressing part adapted to compressing the fluid; and a weight attached to the sealed case and having a predetermined mass for reducing vibration and noise generated by the internal structure, the weight comprising: a neck portion extending from a contacting portion contacting the sealed case, wherein the neck portion is bent; and a free end portion formed by bending the neck portion and spaced apart from the sealed case.
 7. The compressor according to claim 6, wherein the weight has a predetermined area and is attached to the inner surface of a lower side of the sealed case.
 8. The compressor according to claim 6, wherein the weight has a predetermined area and is attached to an outer surface of a lower side of the sealed case.
 9. The compressor according to claim 6, further comprising a spring disposed proximate the neck potion.
 10. The compressor according to claim 6, wherein a portion of the weight is welded to the sealed case by spot welding.
 11. The compressor according to claim 6, wherein the weight is used when the compressor is rotated at a high rotation speed faster than 2,800 RPM so that vibration and noise are reduced.
 12. The compressor according to claim 6, wherein the neck portion is thinner than the free end portion.
 13. A compressor comprising: a sealed case; an internal structure having at least a driving part disposed in the sealed case to generate a driving force to compress a fluid, and a compressing part for compressing the fluid; and a weight attached to the sealed case and having a predetermined mass, wherein the weight reduces vibration and noise generated by the internal structure, and wherein the weight comprises: a neck portion extending from a contacting portion contacting the sealed case, wherein the neck portion is bent; and a free end portion formed by bending the neck portion, wherein the free portion is spaced apart from the sealed case, wherein the free end portion is bent and a part thereof is welded to the sealed case.
 14. The compressor according to claim 13, wherein the weight has a predetermined area and is attached to an inner surface of a lower side of the sealed case.
 15. The compressor according to claim 13, wherein the weight has a predetermined area and is attached to an outer surface of a lower side of the sealed case.
 16. The compressor according to claim 13, further comprising a spring disposed proximate the neck portion.
 17. The compressor according to claim 13, wherein the contacting portion of the weight is welded to the sealed case by spot welding.
 18. The compressor according to claim 13, wherein the weight is used when the compressor is rotated at a high rotation speed faster than 2,800 RPM so that vibration and noise are reduced.
 19. The compressor according to claim 13, wherein the neck portion is thinner than the free end portion. 